Monday, September 15, 2014

We recently
confirmed that Polar, one of our Serena hyenas, has had a cub! As far as we
know, this is Polar’s first cub (or at least it’s the first that has survived
long enough for us to see it). It is looking very healthy, and Polar is a very
attentive mother.

Prepare yourself for adorable photos:

Polar's baby poking its head out of the den

Polar getting her cub out of the den so it can nurse

The first time Molly and I saw
Polar’s cub was pretty amusing. We had Polar at the den hole, and a black cub
emerged from the den and appeared to be trying to nurse. Polar seemed rather irritated
with the cub and would kick it off a nursing position with her hind leg. She
finally got so annoyed that she tried to bite it. Molly and I were aghast at
Polar’s lack of mothering skills and figured we shouldn’t get too attached to
this obviously doomed cub. But lo and behold, a second, smaller black cub
popped out of the den hole and started climbing all over Polar. She tolerated
this with aplomb, and we later confirmed this was fact Polar’s cub when we saw
it nurse. We later realized Polar was sharing her den with another mom, Diggory,
and Diggory’s baby had been trying to nurse from Polar. It is not actually
uncommon for cubs to try and nurse from the wrong mother, but they are usually
quickly told off.

Polar telling Diggory's cub off

Polar putting up with her own pain in the butt cub

Diggory and Polar are keeping their cubs miles away from the
communal den, where the older cubs hang out. Moms keep their babies in dens
isolated from the rest of the clan while they are still very young. Diggory and
Polar are both very protective of this den hole, so woe to any lower ranking
hyena who wants to come say hi to the babies. In fact I’ve even seen Diggory
chase and snap at Lady, a higher ranking hyena, because he dared to come within
5 meters of her den hole.

Diggory and Polar getting ready to chase off a male who
was silly enough to come within 30 meters of their den.

Polar chasing off some big cubs from the den hole

You might think these ladies are over-reactive bullies who
terrorize anyone in the vicinity of the den hole. However, female hyenas have a
very good reason to be defensive. Young cubs are easily killed by predators and
adult hyenas of either sex.

On the other hand, this still doesn’t explain why Polar was
so grumpy when a hungry cub tried to sneak some milk.

Hyena mothers have good reason to
try and hoard resources for their own cub. The skull and jaw muscles of a young
hyena take a particularly long time to develop compared to other mammals. This
is because they need to develop the unique ability to crush bones. During this
time of development, which lasts about three years, hyenas can’t eat their
normal food very quickly. When you’re competing with clan-mates, which can
devour an entire wildebeest in 15 minutes, this could be a serious liability (I
grew up in a human family of four,
and I’m still not sure how I survived being the slowest eater). Moms play an
important role in ensuring their slow-feeding cubs get enough to eat in two
ways: 1) Moms aggressively displace other hyenas at carcasses so their precious
baby has time to feed. 2) Moms nurse cubs for prolonged periods of time, up to
2 years. Therefore, cubs rely on mom heavily for all their food for a long
period of time. So yes, hyena moms have particularly good reason to be grumpy with
anyone trying to steal food from their cub.

Help Support the Research

You can help support our research by making a donation to the Hyena Research Fund at MSU. Your contributions provide necessary resources for the students and scientists to continue our work. Use the link below to make a donation or contact MSU for additional details.